A few years ago I got a used Trek 920 rigid steel mountain bike, it has 9 speeds on the rear and 3 on the front, and W shaped handlebars. This bike fits me very well and is a joy to ride. It needed tires, I wanted tires for mostly street riding that held air well and did not get flats.

After doing some reading online, the decision was made to get Performance Gotham tires in 26" x 1.75", these tires are said to be flat resistant. At the same time I got the tires I also bought the very thick tubes and put a lot of slime in them. So far, so good.

On the bike path, the first thing I noticed was that my coasting speed was much reduced. Using the old tires, I had to ride the brakes on descents to keep from passing my wife, who was also coasting. Using the Gotham tires at 60 psi, our coasting was much more closely matched. On the level and when climbing, more pedaling effort was needed with the Gothams, as compared to the old tires and my other bikes, the difference was noticeable and I'm pretty insensitive to that sort of thing.

Yep, I had discovered a high rolling resistance combination. Part of the reason is probably the deep tread pattern and squishy tread compound, tread deformation absorbs power. Then there is the anti flat construction of the tire, that too has to cause increased rolling resistance. Thick tubes have always caused additional rolling resistance, when I've used them, this time was no exception. Finally, the generous amount of slime, a viscous liquid, has to absorb power too. This result was predictable.

Flats? Nope. Holds air well? Yep. Ride quality? Good. I especially like to not use the air pump frequently.

Then there is another good thing about these tires. I mounted a Straton friction drive ICE engine on the bike, it uses a 33cc Subaru Robin engine, with a 1" roller. In about 300 miles there has been no noticeable wear on the rear tire. Besides that, the roller has good friction against the Gotham tire.

Before putting on the Gotham tires and thick Slimed tubes, the bike got 138 mpg, with pedaling assist. After, the highest was 119 mpg, but this was also at a much higher speed. So, the comparison is sort of skewed.

Would I buy these tires again? No. Reason: the Kenda unknown model tires on my wife's Townie and on my FS MTB, hold air well and have much less rolling resistance. Sometimes less is more. Especially when it comes to rolling resistance.

Lots of slime is a good reason for rolling resistance. 4oz is more than enough IMO.
Then, fresh tires always have more rolling resistance, not for long.
Softer gum is making some rolling resistance too, but I doubt those tires are soft gum.

I also bought those Forte Gothams (13 months ago) from Performance Bike for my first e-bike conversion. I'm not a bike tire expert. Just picked them for the low price point. Also figured the puncture resistance claim was just hype, but I guess they are heavier. My bike with motor/battery pushes 55 pounds. Don't matter at my speeds. Good cheap tire for pavement, seems to be the consensus review on the Performance website.

I "think" my old steel Trek 800 pedals ok at bike speeds with those tires, but I hear you about effect of the tread pattern.

Rubber, nylon of any other plastics, are measured for hardness and this "gum" density has a number and a letter. 60A is the most common tire gum for bicycles, and the type of gum is usually written (small) on the sidewall as Nylon, Latex, etc... Tires are made as soft as 40, from 50 down it is called soft gum and it is wearing much faster. 60 and up is called hard gum. Some tires are made with hard gum with the sole and knobs in soft gum, called double compound. You can also see some triple compound on highly specialized tires. The softer the gum, the better the traction and adherence, and the shorter the life expectancy.

Liquid in a tire does slow it down, especially in both acceleration and braking. That is why adding slime is not good for performance. If you do, it should be little of it. 4 Oz is a good compromise in a +2 in. tire, enough to stop a leak but not too much performance loss.

MikeSSS wrote:...details about them and tell us how they ride.

My bikes are specific builds. The street bike is very fast, above 70 Mph and beats any other vehicle on the city streets in handling, braking and acceleration. It is low and very sticky to the pavement. Don't be fooled by the high front on the picture, the fork is set to sag half of its travel when I am on the bike. It does handle its top speed so comfortably that it could be doubled and it is common for me to leave the handlebar and coast at 35 Mph. It is built on a Session 10 frame.

The dirt bike is much slower, higher, heavier. It does ride very fast for a single track MTB trail though. It is jump-able up to 3ft and I find it is its only downside for I would like higher. Mid drives can jump better, but can't keep up with my speed in the mountain. It is very robust, usually crashes without any damage. It is built on a Santa Cruz V 10 Mk 1 frame.

Like many riders here in the South West, I have to deal w/ Goat's Head thorns, nasty little critters that certain times of the year, even get in to the roadway and hard-surface paths. I tried the usual preventive stop-gaps, extra thick tubes, tubes w. Slime, liners, etc. But not till I combined a "flat resistant" tire w/ an extra thick tube did the flat tire issue disappear. My first combo was the Forte Gotham tire w/ their extra thick tube and although they did stop the flats, there was a price. The Gothams, being a $15 budget tire, does not use Kevlar and the flat resistant layer is very thick and spongy. Combined w/ the extra thick tubes, the resultant ride was very squirmy, almost to the point of being un-nerving.

Gotham.jpg (106.65 KiB) Viewed 1076 times

But when one of the Forte tires developed the cracking shown in the pic(actually, my tire was worse), I switched to a "new to me" tire, the WTB "Slick" hybrid urban;

71xLrDUUE5L._SL256_.jpg (18.83 KiB) Viewed 1076 times

Although the "Flat Guard" is not Kevlar, it's much thinner and even though I'm still using the Forte tubes, the squirminess is much reduced. And overall, the $26 WTB tire is much nicer than the Forte. And I really like the 1.85" size, probably the largest tire that will fit the standard Ebike kit rim comfortably and they seem to hit the right balance of a little extra ruggedness an Ebike needs while still retaining a bicycle tire feel.
I also like the bold graphics, they look sharp.